Tool for drilling polygonal holes



Feb. 26, 1935. R. BARTHoLoMus 1,992,346

TOOL FOR DRILLING POLYGONAL HOLES med nec. 29, 1932 E E: v Ig! Ig7` IgA? Patented Feb. 26, 1935 1 t UNITED STATES PATENT OFFIC 1,992,346 TOOL FOR DRILLING PGLYGONAL HOLES Rudolf Bartholomus, Berlin, Germany Application December 29, 1932, Serial No. 649,377 In Germany October 15, 1930 3 Claims. (Cl. 77-61) My invention relates to tools for drilling polyg- Referring now to the drawing, and first to Figs. onal holes 1n which two camming members are 1, 3 and 4, 1 is the casing of the tool, here shown arranged co-axia'lly in a casing in spaced-apart as a hollow cylinder with a thickened flange at relation for guidmg the drill. its outer end. 2 is a spindle to which the inner 5 It 1s an obJect of my invention to improve a end of casing l is secured. The spindle 2 may be G tool of the type referred to so that it will drill inserted in the headstock of a lathe (not shown) parallel .and not distorted holes. or supported by any other suitable means. It does -To this end, I. arrange the camming members not rotate butis fed axially. with corresponding camming faces' in the indi- 4 is a movable, and 4a is a fixed camming memvidual members angularly displaced relatively to ber in the casing 1. The camming members 4 l0 each otherI to such an extent as will compensate .and 4a are annuli, as shown for the member 4 -for the twist of the drill due to drilling resistance. in Fig. 3, with holes therein for guiding the drill Distortion of the drill under the reaction of the '7. By way of example, camming members for a cuttmg pressure at its edges is inevitable and square hole have been .illustrated but it is underwould lead to the formation of a correspondingly stood that I am not limited to any particular l. distorted hole if the distortion were not countershape of the hole. The movable member 4, as acted by my angular displacement of the cambest seen in Fig. 3, has two lateral lugs 1a in dimms members. ametrically opposite positions, which engage in It 1s another object of my invention to so deparallel. grooves of the casing 1. In this manner sign a tool of the type referred to that seizing of the movable camming member is free to move 20 the edges of the drill is eliminated. Seizing is axially in the casing but held against rotation due to the varying Width of the chips which are therein. 'Ihe other camming member 4a is fixed removed in the drilling of polygonal holes, and in the portion of the casing which is thickened by I frequently causes breaking of the edges. the flange. 8, 8a are two pairs of chucking screws With the object of avoiding seizing, I make one for holding the xed camming member 4a in the 25 of the camming members xed, and the other casing 1. The lugs la of the movable member 4 movable in the casing, and insert a spring between or the holes or depressions for receiving the inner the two members. Tension is put on the spring ends of screws 8, 8a 1n the fixed member 4a, are as the drill, or the work, as the case may be, is singularly displaced through a small angle with fed. When the feeding pressure is removed, the respect to the holes in the camming members, aS 30 spring immediately lifts the end of the drill oir the shown to an exaggerated extent in Fig. 3, the angle bottom 0f the hole so that the edges will not corresponding to the amount 0f distortion the drill seize and break. 7 undergoes under the reaction of the cutting pres- Itis still another object of my invention to prosure. Consequently corresponding guide faces of vide means for facilitating the location of the drill the tWO Camming members, Which are located 35 with respect to the hole. similarly with respect to said lugs and holes, are To this. end, I provide a locating plate between Similarly Out 0f angular phase Witheach Otherthe work piece and the drill casing. In this manner, the distortion of the drill is com- IIl the accompanying drawing, two construcpensated and the Walls of the holes become plane.

tional forms of tools for drilling square holes, In addition to the screws 8, 8a for chucking the 4o which embody my invention, are illustrated by fixed member 4, Screws 16, Fig. 4, are provided way of example. for chucking. a bar or rod 10 in the casing in whose In the drawing inner end the square hole is drilled. The bar or Fig. 1 is an axial section of a tool for drilling rod 10 is held on the face plate 20 of a lathe by a square hole in a rotating rod, chuck jaws 12. It will be understood that while 45 Fig. 2 is an axial section of a tool for drilling the casing 1 rotates with the bar or rod 10, the a square hole in a xed plate, spindle 2 is held against rotation, as described.

Figs. 3 and 4 are sections on the lines III-III 6 is a coiled spring inserted between the xed and IV-IV, respectively, in Fig. 1, and movable camming members 4 and 4. 5 is Fig. 5 is a plan view of the locating appliance a block which is mounted to` slide on the mov- 50 referred to, able member- 4, and 5a is a set screw for holding Fig. 6 is an end elevation of its slotted plate. -the upper end of .the drill 7 in the slide block 5. viewed from the left in Fig. 5, and 5b is a slot in the block 5 in which engages a pin Fig. '7 shows a locating device used with the 3*. 'I'his pin is secured to the lower end of a pismachine. ton 3 which is mounted to rotate in the casilm 1 55 and is connected to the spindle 2. In the present 'Y press. 21 is end of casing 1, it is held by instance, as the casing 1 rotates, and the spindle with the piston 3 is the piston. 1'1 is a ring which isheld at the upper end oi. the easing 1 by set screws 17* lor holding the piston 3 against axial displacement in the casing 1.

For the supply and/or circulation of a lubricant or coolant, a bore 3b is formed in the piston 3, and the casing 1 has comparatively large openings 1". Y Y

In operation, rotation is imparted to the ,casing 1 from the face plate 20 through the b'ar or rod 1o. The casing rotates on the piston 3 as its journal. The block 5 and the drill 'I are held against rotation by their connection to the xed piston 3. The drill only performs reciprocating movement transversely to its axis in the holes of the -camming members 4 and 4a. The spindle 2 and the piston 3 are fed and the spring 6 is compressed by the feeding movement; The section of the drill l andthe coniiguration ofthe faces in the holes of the camming determined that they impart to. the drill the movement required for drilling a square hole as the camming members rotate with the casing 1. Lubricant and/or coolant circulate through the passages 3b and the openings 1 which latter may alsovserve for removing the chips. f

The spring 6 which is compressed as the drill 'l is fed, applies the fixed camming member 42 to the end of the har or rod 10 so that the drill Z is reliably guided from the beginning of the operation., As the drill penetrates into the hole, the movable eamming member 4 moves gradually nearer to the nxed member and compresses the spring `f5 which thus counteracts the feeding movement and raises the drill from the hase oi the hole as soon as the spindle 2 is retracted', preventing seizing and damage to its edges.

lnsteador" a coiled spring as shown a helical spring @not shown) might be provided which when compressed is laid down dat like a spiral. This permits reduction oi the length of the portion of the drill which projects from the uned camming member 4a Without reducing the depth of the hole which can be drilled.

My novel tool may be adapted to any machine for rotary'movement-oi the work, such as a lathe, Fig. l, a turret lathe, or the like, but it may also be adapted to a machine in which the tool rotates, such as a drill press. In any case, if the worh rotates as in Fig. 1, the casing 1 and the cam-- ming members 4, ia rotate While ii the work does not rotate the casing and thecamming members are xed.

Fig. 2 shows my novel tool asi-applied to a drill the table of the press, and 11 is the work on the table. Here, the casing 1 is ilxed and may be connected to the work 11 by a plate 14 which holds the casing against rotation. The spindle 2 and the piston 3 rotate. Their rotation is transmitted to the drill 'TI which rotates and Vreciprocates transversely to its axis under the guidance of the camming members 4, 4*. While in Fig. 1 the xed cammingmemher 4? is held by the screws`8 which are remote from the lower the screws 8* at the lower end in Fig. 2. The piston 3 is now nearer to the lower end of the casing 1 and this Ais made up for by inserting a distance'sleeve 18 between the piston 3 and the annular holder 17.

xed, the casing rotates onY 14 is placed on the work 11 members 4, 4* are so 'the casing and with its drill Locatie for connecting the casing to the the drill and the hule, 6

The means work and for locatingand 7. 15 are pins or studs on the plate 14 which engage in holes at the lower end oi the casing 1 and prevent rotation of the casing. The plate and is then adjited with respect to the casing until its studs 15 engage in the holes in the casing. The

'and the plate 14 are then chucked or clamped on the table 21.

19 is a T for locating the hole. Its arms intersect where two diagonals o the polygonal hole intersect, and the arms must register with the diagonals. In operation, the T is placed on the work 11 in the position shown in Fig. 5, with its arms registering with the two diagonals or the square hole. The arms of the T of the plate 14 and the plate must not be to the work unless the arms of the T 19 are in proper position with respect to the diagonals.

1. A tool for drilling polygonal holes comprising a drill with a shank having a cross-section in the form of a polygon with curved sides, a casing, two axially separated guides in said casing for determining drill movements transverse to K of the guides being axially movable in the casing and the other being stationary therein and both having polygonal guide holes therein, means for securing the movable guide against rotation relatively to the casing, and additional means for securing the stationary guide in the casing and with its drill guiding suriaces displaced through a predetermined angie relahvely to the drill guiding surfaces ci the movable guide;

2. .a tool ior polygonal holes comprising a drill a shank having e. cross-section in the form oi a polygon with curved sides, a casing, two axially separated guides in said easing :for determining drill movements transverse to the drill one of the guides being mail? movable inthe casing and the other oe'mg stationary therein and both having polygonal guide holes therein, means for securing the movable guide against rotation relatively to the camine',

additional means ror securing the stationary faces displaced through a predetermined angle relatively Yto the drill guiding surfaces oi the movable guide, and means :for automatically retracting the drill trom the drilled hole when the feeding pressure is removed.

3. A tool for drilling polygonal holes comprising a drill with a shank having a cross-section in the form of a polygon with curved sides, a casing, two axially separated guides in said easing for determining drill movements transverse to the drill axis, one of the guides being axially movable in the casing and the other being stationary therein and both having guide holes therein, means for securing the movable guide against rotation relatively to the casing, means for ijsecuring the stationary guide in guiding surfaces displaced through a predetermined angle relatively to the guiding surfaces or the movable guide, and a spring in said casing between the movable and thestatioary guides.

RoDoLF naa'rnormriius.

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